Signaling



Patented June 14,1927.

' UNITED STATES PATENT OFFICE.

A-OBEIRT C. MATHE, OF WYOMING, NEW JERSEY, ASSIGNOR T WESTERN ELECTRIC COMPANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

. alemania.

Application inea' Augm as, 1924. semi 1ra. 734,150.

This invention relates to alternating currentsignaling, but more especially has to do with the adaptation of carrier multiplex telegraphy to loaded submarine cables.

In thepresent type of carrier multi lex' telegraph system, such as that employe on land lines, current values of Vdifferent frequencies are allotted to the respective si naling channels and transmission may be e ected by the simultaneous application of several current frequencies to the line. Owing to the very character of the line, the impedance of which remains substantially constant irrespective of current changes, and the apparatus employed, which comprises vacuum tubes operated on the linear portion of the characteristic curve, no appreciable intermodulation or interference between the several current frequencies results. However, in the case of loaded cables, which preferably are continuously loaded with a magnetic material characterized by extremelyhigh permeability at low magnetizing forces, any considerable variation in the current produces a relatively large change in the permeability and, consequently, in the impedance of the cable, so that Crossfire er intermodulation of the several channels results when the current frequencies are applied simultaneously. These factors render the present type of -carrier multiplex telegraph system unsuitable for operation with continuously loaded cables of considerable length which require relatively large sending energies.

It is an object of the present invention to `Vovercome the difficult described in the previous paragraph and7 thereby increase the signaling capacity of inductively loaded cables.

Another object of the invention is to employ a plurality of alternating currents of different frequencies to signal in a novel manner. y

In the embodiment of the invention chosen for illustration, a plurality of transmitters, each capable of selectively providing combinations of signaling impulses in accordance lwith selective operations, are simultaneously brought into operative relation with eIectroi responsive devlces which control the application of a predetermined current frequency to the cable to impart thereto, in succession,

vthe current frequencies representing the vaa suitable electro-filtering device responsive to currents of particular frequencies for re. cording the action of the received currents.` The invention is adapted primarily to the Baudotor five-unit. code and accordingly has been shown applied to such a system, but itis not limited to use in this particular type of system.

A better understanding ofthe invention may be had from the following description when taken in conjunction with the acconipanying drawing which, for the sake of clearness, shows only so much of the system as is necessary for an accurate understanding of the invention. 1

Referring now to the drawing, stations A and B constituting transmitting and receiving stations, respectively, are connected by a continuously loaded cable 5. This continuously loaded cable 5 is constructed in accordance with the preferred form of the invention fin a manner similar to Athat described in patent to O. E. Buckley 1,586,874, June 1, 1926. For more detailed information as to the construction and characteristics of the cable, reference should be had to the noted patent which describes in detail the features of the 4continuously loaded cable.

The transmitting and receiving mechanisms shown at stations A and B are shown diagrammatically, as the specific details of these 9o mechanisms are well known and especially since the invention is not directed to these mechanisms per se.

yEach of the transmitters, whiehis adapted to selectively and simultaneously impart val rious code'combnations of message impulses comprises a plurality of circuit controlling elements 9, 10, 11, 12 and 13, each consisting of .a movable element which cooperates with a pair of fixed contacts. Normally, the movable elements are in engagement withthe left hand tixed contact which is connected to thenegative terminal of battery 15. Each of the selectable elements 9 to 13, inclusive, is adapted to cngageeither of its cooperatingI contacts l'or applying either positive or negative current impulses to an electroresponsive device, as will be later described.

'there may be as many transmitters, each composed of selectable elements 9 to 13, as desired, each transn'iitter being allotted to a particular section or quadrant of the associated synchronous multiplex distributor. The system illustrated in the drawing is arrin'ig'ed for four transmitters to each distributor. The transmitters associated with the di tl'erent quad 1ants of the various distributors are successively brought into operative relation with the associated clectroresponsive device and thence to the cable 5 by suitable rotating brushes.

'lbe selectable elements 9 to 13, inclusive,

.of the several transmitters may be selectively operated in a number of diti'erenty ways. ln the preferred form ol the. invention these selectable elements are. operated automatically in accordance with the pcrforations appearing in a previously perfm'ated tape, which is brought into operativerelation with the selectable element-s 9 to 13.

The synchronous multiplex distributor 17, which is adapted to successively connect the transmitters associated with that distributor with the associated electroresponsive device aud thence to the cable 5 comprises a segmented ring 19, a continuous ring 19 and [t brush arm 2t), which carries a brush for bridging` the smaller segments with the continuous ring 19 and which is fixed to a shaft 21) 'lhe shaft 21 is adapted to be rotated by power communicated thereto from a contiuuous rotating motor and is arranged to be maintained in syncln'onism with similar distributors at the receiving station. lt is noted that the apl'iaratus for maintaining syn-A clnonism has not been shown as this particular n'lcclianism does not, torm a part of the present invention and also sinceV `such mechanisms are Well known to those skilled in the art. The continuous ring 19 of the distributor 17 is connected to polarized relay 1G, controlling a plurality of contacts 24, 25, 26 and 27. -Each of these contacts is individual to a source of alternating current', such as 30, 31. 32 and 39 and upon cach operation of the relay 16, two of these sources of alternating current are connected to the associated circuits. but as will be described later but one of these sources is connected to the continuous loaded cable 5. extending to station B.

ln order to provide a plurality of channels of communication other distributors similar to distributor 17, such as 35 are provided, which successively associate transmitters designated by the numeral 37 with a similar' electroresponsive device 38. The various distributors bear the same phase relation with respect to each other by mounting the brush arms, such as 36, on the same shaft as brush arm 20. The selectable elements of the transmitter 37 are successively connected to the windings of polarized relay 38, which controis the operation of contacts 39 and 4() and it is through these contacts that one of the two sources of alternating current connected to the associated circuits upon each operation of the relay 1G is selectively connected to the cable 5.

At the receiving station B, the currents impressed on the continuously loaded cable 5 by the operation of the relays 16 and 38 pass through a plurality of electro-filters 50, 51, 52 and Each filter 50, 51, 52 and 53 comprises inductance and capacitance, which a re so proportioned in accordance with wellknown laws of alternating current phenomena, that each filter is responsive to currents of only a particular frequency, being practically unresponsive tol currents of all other frequencies. In the system disclosed thc tiltcr 5() is responsive only to currents of the frequency supplied by the alternating current source 30, filter 51 to currents of the frequency supplied by the alternating current source 32, filter 52 by the currents from the alternating current source 31 and filter 53 from the currents of the alternating current source 33. Each of the filters 50, 51, 52 and 53 has its output circuit operatively connected to a winding of each of multiple contact relays 54 and 55. Each of these relays will thus be selectively operated in accordance with the particular frequency impressed on the litters and Will in turn control circuits extending to distributors 58 and 59. Each of these distributors 58 and 59 simultaneously connects printing telegraph re ceiving printers 60 and 61 with the contacts of the relays 5ft and 55. Inasmuch as the distributor brushes of each of the distributors 58 and 59 bear substantially the same phase relation as the distributor brush arms 2O and 36 of the transmitting distributors 17 and 35, respectively, they will traverse corresponding quadrants of associated distributors simultaneously.

The operation of the system will now be described. Assume for the sake of illustration that tapes previously perforated in accordance with the various code combinations of impulses representing the message pass through the tape transmitters' 8 and 37 simultaneously. The tapes passing through the transmitters 8 and 37 will in all prob-l ated in dilferent combinations. Also assume that the selectable elements 13 of each of the transmitters has been moved so that they engage the right hand contact. Then too, that the selectable elemeut12 of transmitter 8 remains in the position shown While the corresponding selecting element of transmitter 37 has been moved lto engage its right hand contact. On the passage of the brush carried by brush arm 20 on to the segment individual to the selectable element 13 positive current is supplied through the continuous ring 19 to the windings of relay 16. Simultaneously with this operation the brush carried by the distributor brush arm 36 engages the segment individual to they corresponding selectable element of the transmitter 37 and applies through its continuous ring positive current impulse to the windings of relay 38. Each of the relays 16 and 38 thus reverses the position of its armature, relay 16 closing contacts 24 and 25 and opening contacts 26 and 27 while relay 38 opens contact 39 and closes contact 40. The closure of contacts 24 and 25 of relay 16 connects the alternating current sources 32 and 33 with the contacts of relay 38, but inasmuch as but one of these contacts is closed, but one of the alternating current sources will be connected to the cable 5; in this" particular case alternating current source 33 is connected through the contact 24 of relay16 and contact 40 of relay 38 with the cable 5.

The impulse from the alternating current source 33 upon being received at the receiving station B traverses the input circuits of each of the filters 50, 51, 52 and 53. As previously stated, these filters are made responsive-.to a particular alternating currentr frequency and in the particular case s lected the filter 53 responds to current froi the alternating current source 33. A cut'- rent in accordance with the impressed Aalternating current is ap lied to the output circuit of the filter 53 W ich passes through 4the lower right hand Winding of relay 54 and the lower left hand winding of' relay 55. In the case of relay 54, its armature will be positionedV to connect the positive a terminal ofbattery with the continuous ring of the distributor 58. Likewise vrelay 55 moves its armature to also connect the positive terminal of the battery to the continuous ring of the distributor 59. Inasmuch as the distributors 58 and 59 operate in synchronism With the distributors 17 and 35 at the transmitting station A, the segments corresponding to the segments individual to the selectable elements 13 of each ot the transmitters 8 and 37 will be connected with the continuous ring through a suitable brush at the instant the relays 54 and 55 respond to the transmitted impulse for elieeting the operation ot' the associativi electromagnets of the receiving' printers 60 and 61. It should be noted that both oi the. transmit.- ters-S and 37 were operated to transmit a positive impulse; accordingly relays .51 and 55 at the receiving station B were operated for applyingr through the distributors and 59 to the receiving printers 6() and 61 simultaneously a corresponding impulse.r

Now with the selectable elements 12 ot'each of the transmitters 8 and 37, one in the position shown inA thedrawing and the other in its opposite position, the relays 16 and 38 will be operated upon the engagement of the brush ot"V the associated distributor with the segment individualto theparticular selectable element of the transmitter. In the case of the relay 16 its armature is caused to reverse its position, disconnecting the alternating current souries 32 and and connecting the alternating current sources 30 and 31 through the contacts 26 and 27. Simultaneously with the operation of relay 16, relay 38 is operated for again closing contact 40. The operation of the relays 16 and 38 in this manner now connects the alternating current source 31 with the cable 5.

The impulse from the alternating current source 31 upon being received at the station B passes through each of the filters 50, 51, 52 and 53. but imparts current to only one ot' the output circuits of these filters.` In this 'particular case current fiows in the output circuit of the filter 52 through the upper right hand winding of relay 5i and `lowerright hand winding of relay 55. The

of battery with'the distributor 59. The operation of the selecting magnet of 'the receiving printers 60 and 61 is etiected in a manner similar to that previously described.

The invent-ion has been illustrated for two channels of communication but obviously the system may be extended for providing additional channels of communication. Should more channels of communication be desired, it is only' necessary that additional distributors be provided and additional contacts on each of the relays whereby the number ofselective combinations may be effected for the transmission of a single alternating current frequency designating the combinations of plus and minus impulses. At the receiving station additional equipment must also be provided for a;comuiodating the added channels ot communication. In general it will be seen that for n channels, 2 distinct frequencies will be needed for using this method of operation.

The invention has been disclosed and described With reference to a particular type of system but it is not intended that the roo invention should be limited to this particular type of system as obviously various modilications may be made without departing from the spirit and scope of the present invention.

What is claimed is:

l. The method of gence which comprises generating alternating currents .of a plurality of different single frequencies, selecting each of said currents respectively to represent portions of a plurality of messages and transmitting said currents only in succession.

2. The method of transmitting intelligence which comprises transmitting an alternatin;r current of (onstant single frequenc that represents portions of a plurality of separate messages -and utilizing said current to cause simultaneously a plurality of separate indications respectively corresponding to said message portions.

3. The method of transmitting intelligence which consists in generating a plurality of alternating currents of different, pure, frequencies, applying the currents of ditferent frequencies to a signaling patlr in succession and utilizing each current to designate various combinations of impulses of equal duration, each impulse in part representing' a code character.

4. rlhe method of transmitting intelligence from a plurality ot channels simultaneously over an inductively loaded conductor Which' comprises applying portions of separate messages simultaneously to said conductor by means ot' one of a plurality of alternating currents of diil'erent, single frequencies, and similarly utilizing the other currents of different frequencies, and utilizing the selected single Afrequency current to represent a combination of impulses of equal duration, each .combination consisting of portions of separate messages.

The method of receiving intelligence transmitted electrically through the successive application of alternating currents of different frequencies, each representing a com-- bination of impulses for portions of separate messages, which method comprises filtering the several currents ot different frequencies, and utilizing the iiltcred current of each frequency to control the simultaneous recordation of the portions of the plurality of messages represented by the current of that frcquei'icy.

G. In a telegraph'systeima line connecting two stations, a plurality of transmitters arranged to be selectively and simultaneously operated. in various combinations. a plural` ity of soui'ces oi current of diii'erent frequencies. and means operable tor connecting any one of the said diit'erent sourcef'-` of current to said line in accordance nith one of the combinations set up by the simultaneous operation of said transmitters.

transmitting intelli- 7. In a telegraph system, a line connecting two stations, a plurality of transmitters each arranged to be selectively operated in various combinations, a plurality of sources of alternating current of different, single frequencies, and electro-responsive means controlled by said transmitters for successively imparting, to said line, current impulses of different, single frequencies each representing a combination of separate message impulses.

8. In a telegraph system, a line connecting two stations, a plurality of transmitters each arranged to be selectively operated in various combinations, a plurality of sources of alternating current of different, single frequencies, and electroresponsive means individual to each of said transmitters and controlled thereby for successively imparting to said line current impulses of different, single frequencies each representing a combination of separate message impulses.

9. In a telegraph system, a line connecting two stations, a plurality of transmitters each arranged to lie selectively operated in various combinations, a plurality of sources of alternating current of different, single frequencies. and multiple contact relays energized in accordance with the operation of said transmitters for selecting the particular current frequency designating the combination determined by said transmitters and imparting corresponding current to said line.

l0. In a telegraph system, a line connecting two stations. a plurality of transmitters each arranged to be selectively operated in various combinations, a plurality of sources of current of different. single frequencies, means operated in accordance with the operation of.said transmitters for selecting and connecting `the different sources of current successively to said line` and distributing means for simultaneously associating said transmitters with said means.

l1. In a telegraph system, a line connecting two stations, a plurality of transmitters at one of said stations, means for rendering said transmitters effective simultaneously durinf.r each impulse period, electro-responsive means controlled by said transmitters for imparting to said line during each period an alternating current impulse of .a frequency dependent on the combination set up on said transmitters, receiving means associated at the other end of said line comprising a plurality of recording instruments, and selectively operated means controlled by the incoming combination for causing the simu taneous operation of said instruments in accordance with the code combination transmitted by said transmitters.

l2. In a telegraph system, a line connect- I ing two stations, a plurality ot transmitters at one of said stations, means for rendering said transmitters effective simultaneously during each impulse period to transmit p ortions of separate messages, electro-responsive means controlled .by said transmitters for imparting to said line alternating current impulses of a frequency dependent on the-combination set up on said transmitters, 4.receivinggg' means associated at the other end means -controlled by said last mentioned relays associated with said means .for simultaneously registering the irnpulses of a combination on separate recording instruments.

13. In a telegraph system, a -line connecting two stations, a plurality of transmitters at one of said stations, means for rendering said transmitters effective simultaneously, electroresponsive means controlled by said transmitters for imparting to said line alternating current im ulses of a frequency dependent on the combination set up on `said transmitters, receiving means associated at the other end of said line comprising a plurality of electro-filters each responsive to a particular current frequency a number of filters, and' operated to reproduce current conditionssimilar to those set upby rsaid transmitters, and means controlled by said relays for recording the effect of the impulses.

14.-. 'In a telegraph system, a'loaded submarine cable connecting two distant stations, a plurality of transmitters at one of said stations, means for rendering said transmitters effective simultaneously, electroresponsive means .controlled by said transmitters for imparting to said cable alternating current impulses, each ofa single frequency dependent on the combination set up on said transmitters, receiving means asl sociated at the other end of the cable comprising a plurality of recording instruments and selectively operated means controlled by the incoming impulses for causing the operation of said instruments in accordance with the code combination of impulses transmitted by said transmitters. t y

' 15. In a tele raph system, a continuously loaded submarine cable of Variable 'permeability extending' between two distant stations, a plurality of transmitters at one of said stations, means for rendering said transmitters effective simultaneously, electroresponsive means controlled by'said transmitters for imparting to said cable alternatingv current'impulses, each of a single frequency dependent on the combination-set u on said transmitters, and means controlle by said relays for recording the effect of the impulses.

16. In a telegraph s stein, a continuously loaded submarine cab e extending between two distant stations, a pluralityvof transmitters at one of s aidstations, means; for rendering said transmitters effective simultaneously, electro-responsive means controlled by said transmitters for imparting to said cable alternatingcurrent impulses, each of a single frequency dependent on the combination set up on said transmitters, receiving means associated at the other end of said cable comprising a plurality of electroilters each responsive to a articular current frequency, a pair of re ays associated with sai filters, and o eiated to reproduce current conditions simi ar to the setting by said transmitters, and means" controlled by said relays for recording the effect of the impkulses.

1r. In a telegraph system, a line connect-v ing two stations, a plurality of transmitters at one of said stations, means for-rendering said transmit-ters effective simultaneously, electroresponsive means controlled by said transmitters for imparting to said line alternating current impulses, each of a single frequency dependent on the combination set up on said transmitters, receiving means as` sociated at the other end of-said line comprising a plurality of frequency selectingl systems,l electromagnetic relay means controlled by said frequency Selecting systems, a pluralityv of receiving printers for. each transmitter, and distributing means for a'ssociating the receiving printers corresponding to said transmitters simultaneously with said electromagneticrelay means.

18. In'a'telegraph system, a lineconnect-k ving two stations, a plurality of transmitters at one of said stations, means for rendering said transmitters effective simultaneously, electroresponsve means controlled .b said transmitters for imparting to said line alternating current im ulses of. a frequency dependent on the combination set up on said transmitters,'receivin means associated at the other end of said line comprising a plurality of frequency selecting systems, electromagnetic relay means controlled b said frequency selecting systems, a plurality of receiving printers for each transmitter and synchronous multiplex distributors for associating the receiving printers corresponding to said transmitters simultaneously with said electromagnetic relay means.

19. A signaling system comprising a pluvrality of message channels, means associated iis different frequencies, mechanism whereby frequency components than there are chaneach possible combination of signaling elenels. ments, selecting one element from each chan- 1 In Witness whereof, I hereunto subscribe l0 nel7 selects and impresses upon a signaling my name this 28rd vday of August, A. D.

5 conductor a distinctive alternating current 1924.-

from said plurality of sources, said current i y always containing fewer different essential I ROBERT C. MATHES. 

